The Physcio-chemical Items In Aloe Vera Under Sea Water Irrigation And Extraction Of Polysaccharides

This thesis focuses on the analysis of the physcio-chemical items of Aloe vera whole leaf(or whole leaf juice) and its gel (or gel juice) irrigated with different concentrations of seawater. And the optimal isolation conditions of aloe polysaccharides extracted from Aloe verairrigated with 100% sea water with the method of alcohol precipitating and the methods of theremoval of the protein from the crude polysaccharides was studied, respectively.The results indicated that water content of Aloe vera whole leaf and its gel under seawater irrigation had no significant difference among all levels, as well as pH, relative densityand the contents of protein, aloin and flavones of gel juice and the absorbance, pH and proteincontent of whole leaf juice. There were significant changes in the total solids content andabsorbance of gel juice and the relative density and total solids content of whole leaf juiceirrigated with sea water. Sea water irrigation had significant effect on the relative density andthe contents of polysaccharides, anthraquinone, Vitamin C and aloin of the whole leaf juiceand the absorbance, polysaccharides and Vitamin C content of gel juice. The polysaccharidescontent of the whole leaf juice irrigated with 25% sea water was the highest, being 129% ofthat irrigated with fresh water. And the polysaccharides content of gel juice irrigated with100% sea water was 50.51% more than that irrigated with fresh water. The flavones contentof whole leaf juice irrigated with 100% sea water was the highest, which was 41.24% morethan that irrigated with fresh water. Anthraquinone existed in the skin of the Aloe vera.Among all levels, the anthraquinone content of whole leaf juice irrigated with 75% sea waterwas the highest. In the whole leaf juice, the vitamin C content irrigated with 25% sea waterreached the most, being 130% of the control. The vitamin C contents of whole gel juiceirrigated with 10%, 25%, 50%, 75% and 100% sea water were 120%, 163%, 189%, 170% and170% of that irrigated with fresh water, respectively. Aloin was mostly in the skin of the Aloevera. And the aloin contents of whole leaf juice irrigated with 10%, 25%, 50%, 75% and 100%sea water respectively reduced 29.3%,30.89%,26.57%,37.65% and 48.53% compared withthe control, respectively. The content of Ca²⁺, Mg²⁺, Na⁺, K⁺ was high, the content of Mn²⁺,Zn²⁺ and Fe^3+,2+ was medium, however the content of Ni⁺, Pb²⁺, Cd²⁺ and Cr²⁺ was low. Theconcentration of sea water had great effects on the content of Ca²⁺ and Mg²⁺, while little onother elements in the gel or in the whole leaf of Aloe vera. The polysaccharides were extracted from Aloe vera with the method of alcoholprecipitating and water extracting. The results indicated that the content and the amount ofalcohol were of great importance to the polysaccharides extraction amount, but the extractiontemperature and the extraction time were less important. The optimal extraction conditionswere 95% alcohol, the ratio of alcohol and sample at 9:1 and alcohol precipitating at 60℃for30 min.Four methods of the removal of dissociative proteins in aloe crude polysaccharides ofAloe vera irrigated with 100% sea water were optimized, including Sevag method, enzymaticmethod, TCA method and hydrochloric acid method. The optimal conditions of Sevag methodwere: chloroform: 2-butanol (v:v) was 3:1, shaking time was 5 minutes, dual-phase ratio was3:1. Compared with other methods, the Sevag method was the most effective to removedissociative proteins from polysaccharides. Sevag method was quick and convenient, and theloss of polysaccharides was the less.